It is known that reflectors are employed in helio-thermal power stations, such as parabolic-trough power stations, Fresnel power stations, Dish-Stirling power stations and solar updraft tower power stations and the like, in which part of the solar radiation energy is converted to heat with the aid of absorbers. Typically with such systems, solar radiation is concentrated in order to increase efficiency in the utilization of solar energy.
As components of so-called “collectors” in helio-thermal systems, the reflectors serve for focusing the incident sunlight and for concentrating the latter onto an absorber, for example an absorber tube or the like, which carries a heat transfer medium. Here, there is the requirement that the reflectors have optimum reflective capability in the radiation spectrum of sunlight, on the one hand. On the other hand, the reflectors are to be as robust as possible in relation to the mechanical stresses arising during use and to be manufacturable as cost-effectively as possible. Moreover, a particular challenge lies in guaranteeing the dimensional stability of these components with a usually large area, so as to reliably achieve focusing of the sunlight with the required accuracy over the entire service life of the reflector.
In order for the reflective area of such a reflector to be designed it is known for a glass carrier of the type of a conventional mirror to be unilaterally coated with silver or aluminum. Here, the high weight as well as the low elastic deformability and resistance to mechanical stress of the glass carriers are disadvantageous.
It is known from European patent application EP 1 154 289 A1 for a reflector body of aluminum or of an aluminum alloy having a reflective aluminum surface to be provided. Alternatively, the reflective surface here may also be produced by coating a reflector body with aluminum. A transparent protective layer which is applied to the reflector surface is intended to protect the reflective surface from environmental influences.